“My God!” he exclaimed aloud.  “My God!” He feared to find a crushed and broken little body at the foot of those steep iron ladders.  It seemed impossible for such a frail and aged woman to have, unaided, made her way down the sides of that inky precipice.  “Good Lord!” he exclaimed again, “if only she isn’t killed!” He stood looking out, leaning as far over the iron railing as he dared, waiting till his eyes should become accustomed to the darkness.  Gradually the details of the structure became clear to his vision.  No ominous dark mass took shape on the pavement, far beneath.  He could vaguely make out the contours of an ash can or two and an abandoned wheelbarrow.  But the alley from end to end held no human form.  She had succeeded in making her escape!  Then at all costs he must find her; and the police must not get hold of her.  The evidence of the clippings, her angry words as she prepared to attack Mrs. Marteen—­all outlined a possible solution to the tragedy in Washington Square.

He hesitated a moment.  His first impulse was to descend the fire escapes in turn and look below for further trace of her going.  But he realized that he could reach the alley quicker by going through the house.  He cursed himself for a careless fool.  How could he have allowed this to happen!

He turned quickly, intent on losing no further moments, when he was frozen into immobility by a sound, the most curiously unexpected of all sounds—­a laugh, a faint treble chuckle!  It seemed to come from the outer air, from nowhere, to hang suspended in the damp air of the shaft.  It was eerie, ghostly.  Was the spirit of the dead man laughing at his folly?  The detective stepped back on the grating, flattening himself against the outer sill of his window.  Again the chuckler—­now an unmistakable laugh floated to his ears.  With a smothered exclamation he stepped forward again, and looked upward.  There, against the violet-gray of the star-sprinkled sky, bulked a crouching shape, cuddled on the landing above.

Brencherly held his breath.  It seemed that the woman must fall from her perch, so insecure it seemed.  He controlled himself, thinking rapidly.  Then he laughed in return.

“That was a good joke you played on me,” he said.  “How did you ever think of it?”

“Oh,” came the answer, punctuated by smothered peals of laughter.  “That’s the way I got away from the Sanatorium.  I just went up instead of down, and stayed there, till they’d hunted all the place over.  Then when I saw where they weren’t, I just went down and walked out.”

“That was clever,” he exclaimed.  “But you can’t be comfortable up there.  Won’t you come down, and I’ll get something for you to eat.  You must be hungry, and cold, too.”

“No,” came the response.  “I sort of like it here.  It reminds me of the way I fooled them all back there; and they thinking themselves that sharp, too.  It’s sort of nice, too, looking at the stars—­sort of feels like a bird in a nest, don’t it?”